Am I doing the boost test right?

[davidgt97]

Last week I made my own homemade boost leak test kit. I used two pieces of 2" pvc w/ a cap on each end. In the end of one I threaded in an air valve. I put one end where the turbo output was and the other end at the end of the throttle body hose. I tried to put 15psi in the line but the air was coming out of the BOV(not around the mount, but through it.) I thought I had found my leak (faulty BOV) Today I installed a "good" BOV I bought off EBAY, but had the same issue. I can't build any pressure in the line. Please Help

 

[spoonman]

The proper way to do the boost leak test would have been to not block it off at the TB but, to let the pressure in through to the intake manifold, this would apply the pressure to the BOV and help hold down the BOV's spring keeping it shut. I suggest you do it the right way.

 

[romeen]

No, you are not doing it correctly (if I am understanding you). Hook up only one cap (with the valve obviously) to the compressor inlet of the turbo. Leave the rest of your intake hooked up and intact. This way you will pressurize your intake manifold as well. Listen for air escaping as well as spraying soapy water on all couplers, joints, flanges, etc.

Your BOV is probably fine. It needs pressurized air pushing down on it to help keep it closed under boost. That vacuum line from the IM is providing this pressure under boost (it provides vacuum between shifts to open the valve). Since you were not pressurizing your IM before the pressure in the UICP was just forcing the valve open.

 

[Zmann42087]

I'm not completely sure I understand how you made your boost leak tester... you said you put a PVC cap on both ends? You need one end open so you can attach it to the compressor inlet on your turbo. Anways, talk is cheap, pics are better. Your boost leak tester should look like this.

Once you have your tester built (properly). You just take off your intake pipe and attach the open end off the tester to the compressor inlet of your turbo. Then just pressurize the intake system through the valve on the capped end of your tester. Have a friend keep tabs on the aftermarket boost gauge in your car so you don't overpressurize the system.

Anways, you think you're leaking through the stock BOV? The stock 1g BOV when properly attached and working should hold boost just fine. Is you 1g BOV crushed or uncrushed?

 

[davidgt97]

First of all thanks for the assistance. I didn't know the BOV used intake pressure to hold it shut. Now for the fun part. I did not pressurize the turbo, my line goes in right behind the turbo. I tried to fill the line w/ 20 psi but could achieve no air pressure. I had my wife hold the line on while I slowly turned the motor over by hand. First I could hear a large amount of air so I kept turning until it was quieter but it was never close to silent. I turned the motor to the point where I heard the least amount of air. As she held the air line on I reached around the TB and I could feel a large leak on the bottom side but I have already changed the TB gasket and snugged the bolts back well. I am not sure what the sensors are on the bottom of the TB. Could my leak be from whatever is on the bottom of the TB?

 

[davidgt97]

Anyone? Any thoughts would help.